This invention relates generally to the field of telecommunications and, more specifically, to an insertion/extraction apparatus for circuit cards.
Central offices house numerous telecommunication devices, such as voice gateways, DSLAMs, channel banks, and Class 5 switches. These telecommunication devices typically have multiple circuit cards disposed within a card cage. The circuit cards generally include printed circuit assemblies attached to faceplates. These circuit cards are sometimes referred to as field replaceable units (xe2x80x9cFRUsxe2x80x9d). For various reasons, FRUs sometimes have to be replaced in the field. Therefore, FRUs utilize insertion/extraction devices (sometimes referred to as ejectors) to make it easier for field personnel to insert and extract them from the card cage.
Telecommunications equipment manufacturers take into account many criteria when designing and manufacturing ejectors for use on FRUs, including ease of replacement, low cost of manufacturing, and low emissions. In addition, certain standards affect design. One such standard is a Network Equipment Building Standard (xe2x80x9cNEBSxe2x80x9d) TR-78 standard by Bellcore, which states that FRUs have to be replaceable without tools. Another standard is a safety standard, UL1950, that requires FRUs to be secured down in place. The reason for this standard is to prevent users from touching any hazardous voltage on the backplane of telecommunication devices. Ironically, these two standards somewhat conflict, which makes it difficult for a telecommunications equipment manufacturer to meet both of them when designing and manufacturing ejectors. Therefore, some types of ejectors meet either the NEBS standard or the UL1950 standard, but not both.
Various types of ejectors exist, and one such type adds a captive fastener to the faceplate of the FRU that mates to a portion of the card cage via tapped holes. This results in a much higher cost associated with manufacturing the card cage because of drilling and tapping holes in the card cage. This also means that severe alignment/tolerance problems exist when trying to match up the screws in the faceplate to the holes on the FRU. Some ejectors connect directly to the printed circuit assemblies, which means that large notches or holes exist in the faceplate thereby letting emissions escape from inside the card cages.
The challenges in the field of telecommunications continue to increase with demands for more and better techniques having greater flexibility and adaptability. Therefore, a need has arisen for a new insertion/extraction apparatus for circuit cards.
In accordance with the present invention, an insertion/extraction apparatus for circuit cards is provided that addresses disadvantages and problems associated with previously developed insertion/extraction apparatuses.
According to one embodiment of the invention, an insertion/extraction apparatus for circuit cards includes a card cage having at least one card guide and at least one channel, at least one circuit card engaged with the card guide, and at least one ejector pivotally coupled to the circuit card. The ejector has protrusions proximate a first end that are operable to engage the channel and a fastener disposed through an aperture in the ejector.
Some embodiments of the invention provide numerous technical advantages. For example, a technical advantage of one embodiment of the present invention is that an ejector locks to either itself or a faceplate of a field replaceable unit, which results in a much lower cost of manufacture by avoiding drilling and tapping holes in a card cage or having to use static or floating fastening devices attached to the card cage. Furthermore, alignment and tolerance problems are eliminated, which significantly saves manufacturing cost. Another technical advantage of one embodiment of the present invention is that an ejector manufactured according to the teachings of the present invention meets both the UL1950 safety requirement and the NEBS TR-78 standard. An additional advantage of one embodiment of the present invention is lower emissions emanating from inside telecommunications apparatuses by utilizing ejectors manufactured according to the teachings of the present invention.
Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims.